1. Field of the Invention
The present invention relates to an inkjet printing apparatus and inkjet printing method for printing using a color material-containing ink and color material-free clear ink.
2. Description of the Related Art
Recently, inkjet printing apparatuses have high expectations placed on them to form high-quality images on various printing media. The inkjet printing apparatuses are required to even produce images with photographic image quality, and widely use glossy paper capable to create the same image quality and texture as those of a silver halide photograph.
There are various requirements for images to be printed on glossy paper. For example, a photograph is sometimes decorated with a text and graphic for a poster or the like. Conventionally in decoration, the text and graphic come to the foreground, and a photograph portion under the text and graphic is filled and cannot be seen. Even if the advertisement tries to emphasize both the item and advertising copy, the inserted text and graphic hide part of the item. To insert a photograph so as not to overlap the text and graphic, the photograph needs to be downsized, and the item cannot appeal to customers.
Under the circumstances, there is a demand for printing an image with a special effect that utilizes a difference in glossiness by forming both a highly glossy region and less glossy region on a single printing medium. For example, a text image is printed at low glossiness in a partial region while a photographic image is printed at high glossiness on the entire surface. Such a printed material has an effect in which the text is seen as if it popped up when the user sees the printed material from a different angle. This effect is often used in a discharging purpose “decoration printing” for catalogs and graphic arts.
U.S. Pat. No. 6,193,361 and Japanese Patent Laid-Open No. 2004-122496 describe the use of a colorless clear ink to control gloss in order to achieve the above discharging purpose. In U.S. Pat. No. 6,193,361 and Japanese Patent Laid-Open No. 2004-122496, the scan count in printing the clear ink or thinned data of each scan is changed to roughen the surface and control the glossiness, thereby expressing a plurality of glosses on a printed material.
Both methods disclosed in U.S. Pat. No. 6,193,361 and Japanese Patent Laid-Open No. 2004-122496 change the glossiness by roughening the image surface. These methods decrease the glossiness defined by reflection of light, but worsen haze (image clarity). At a decorated portion, the photograph surface becomes hazy.